Read and traverse the index.

CMakeLists.txt

@@ -2,6 +2,7 @@ cmake_minimum_required(VERSION 3.13)
 project(libdicformat C)
 
 set(CMAKE_C_STANDARD 99)
+add_compile_definitions(__STDC_FORMAT_MACROS=1)
 
 add_library(libdicformat SHARED include/dicformat/consts.h include/dicformat/enums.h include/dic.h include/dicformat.h
             include/dicformat/decls.h include/dicformat/structs.h src/identify.c src/open.c include/dicformat/context.h src/close.c include/dicformat/errors.h)

include/dicformat/context.h

@@ -15,6 +15,16 @@ typedef struct dicformatContext
     uint8_t               libraryMinorVersion;
     FILE                  *imageStream;
     DicHeader             header;
+    struct dataLinkedList *mediaTagsHead;
+    struct dataLinkedList *mediaTagsTail;
 } dicformatContext;
 
+typedef struct dataLinkedList
+{
+    struct dataLinkedList *previous;
+    struct dataLinkedList *next;
+    unsigned char         *data;
+    int                   type;
+} dataLinkedList;
+
 #endif //LIBDICFORMAT_CONTEXT_H

include/dicformat/enums.h

@@ -187,7 +187,7 @@ typedef enum
     /** Block containing a deduplication table */
             DeDuplicationTable = 0X2A544444,
     /** Block containing the index */
-            Index                        = 0X58444E49,
+            IndexBlock         = 0X58444E49,
     /** Block containing logical geometry */
             GeometryBlock      = 0x4D4F4547,
     /** Block containing metadata */

include/dicformat/errors.h

@@ -7,6 +7,7 @@
 
 #define DICF_ERROR_NOT_DICFORMAT -1
 #define DICF_ERROR_FILE_TOO_SMALL -2
-#define DICF_ERROR_INCOMPATIBLE_VERSION -2
+#define DICF_ERROR_INCOMPATIBLE_VERSION -3
+#define DICF_ERROR_CANNOT_READ_INDEX -4
 
 #endif //LIBDICFORMAT_ERRORS_H

include/dicformat/structs.h

@@ -104,7 +104,7 @@ typedef struct IndexHeader
 typedef struct IndexEntry
 {
     /**Type of item pointed by this entry */
-    uint32_t uint32_t;
+    uint32_t blockType;
     /**Type of data contained by the block pointed by this entry */
     uint16_t dataType;
     /**Offset in file where item is stored */

src/open.c

@@ -34,12 +34,21 @@
 #include <dicformat.h>
 #include <malloc.h>
 #include <errno.h>
+#include <inttypes.h>
+#include <string.h>
 
+// TODO: Check CRC64 on structures
+// TODO: ImageInfo
 void *open(const char *filepath)
 {
     dicformatContext *ctx = malloc(sizeof(dicformatContext));
     int              errorNo;
     size_t           readBytes;
+    long             pos;
+    IndexHeader      idxHeader;
+    IndexEntry       *idxEntries;
+
+    memset(ctx, 0, sizeof(dicformatContext));
 
     if(ctx == NULL)
         return NULL;
@@ -82,14 +91,78 @@ void *open(const char *filepath)
         return NULL;
     }
 
+    fprintf(stderr,
+            "libdicformat: Opening image version %d.%d",
+            ctx->header.imageMajorVersion,
+            ctx->header.imageMinorVersion);
+
+    // Read the index header
+    pos = fseek(ctx->imageStream, ctx->header.indexOffset, SEEK_CUR);
+    if(pos < 0)
+    {
+        free(ctx);
+        errno = DICF_ERROR_CANNOT_READ_INDEX;
+
+        return NULL;
+    }
+
+    pos = ftell(ctx->imageStream);
+    if(pos != ctx->header.indexOffset)
+    {
+        free(ctx);
+        errno = DICF_ERROR_CANNOT_READ_INDEX;
+
+        return NULL;
+    }
+
+    readBytes = fread(&idxHeader, sizeof(IndexHeader), 1, ctx->imageStream);
+
+    if(readBytes != sizeof(IndexHeader) || idxHeader.identifier != IndexBlock)
+    {
+        free(ctx);
+        errno = DICF_ERROR_CANNOT_READ_INDEX;
+
+        return NULL;
+    }
+
+    fprintf(stderr, "libdicformat: Index at %"PRIu64" contains %d entries", ctx->header.indexOffset, idxHeader.entries);
+
+    idxEntries = malloc(sizeof(IndexEntry) * idxHeader.entries);
+
+    if(idxEntries == NULL)
+    {
+        errorNo = errno;
+        free(ctx);
+        errno = errorNo;
+
+        return NULL;
+    }
+
+    memset(idxEntries, 0, sizeof(IndexEntry) * idxHeader.entries);
+    readBytes = fread(idxEntries, sizeof(IndexEntry), idxHeader.entries, ctx->imageStream);
+
+    if(readBytes != sizeof(IndexEntry) * idxHeader.entries)
+    {
+        free(idxEntries);
+        free(ctx);
+        errno = DICF_ERROR_CANNOT_READ_INDEX;
+
+        return NULL;
+    }
+
+    for(int i = 0; i < idxHeader.entries; i++)
+    {
+        fprintf(stderr,
+                "libdicformat: Block type %4s with data type %4s is indexed to be at %"PRIu64"",
+                (char *)&idxEntries[i].blockType,
+                (char *)&idxEntries[i].dataType,
+                idxEntries[i].offset);
+    }
+
     ctx->magic               = DIC_MAGIC;
     ctx->libraryMajorVersion = LIBDICFORMAT_MAJOR_VERSION;
     ctx->libraryMinorVersion = LIBDICFORMAT_MINOR_VERSION;
 
-    fprintf(stderr,
+    free(idxEntries);
-            "libdicformat: Opened image version %d.%d",
-            ctx->header.imageMajorVersion,
-            ctx->header.imageMinorVersion);
-
     return ctx;
 }